Quality analysis of tetanus toxoid and diphtheria toxoid bulks

Objective To analyze endotoxin contents, monomer/polymer ratio, and number of free amino groups in tetanus toxoid (TT) and diphtheria toxoid (DT) bulks. Methods Ten batches each of TT and DT bulks were taken. Gel-clot test, high performance liquid chromatography, and trinitro benzene sulfonic acid method were used to detect bacterial endotoxin, monomer/polymer, and free amino groups, respectively. Results The average endotoxin contents of TT and DT bulks were 1.14 and 0.35 EU/Lf, respectively. TT monomer content averaged 72.1%, 3 times of polymer content. DT monomer content averaged 88.9%, 8 times of polymer content. Average number of free amino groups per protein molecule was 43.5 in TT and 9.9 in DT. Compared with their respective toxins, free amino group number after detoxification decreased by approximately 60% in TT and 75% in DT. In both TT and DT, monomer/polymer ratio and free amino group contents showed good batch consistency(coefficient of variation: 1.59%-16.26%). Conclusion Bacterial endotoxin content, monomer / polymer ratio, and free amino group number can be used as detection indicators in controlling TT and DT production process and monitoring the batch consistency of TT and DT. Key words: Tetanus toxoid; Diphtheria toxoid; Endotoxins; Monomer; Amino groups